Impact tool



Dec. 5, 1961 J. B. vlLMERDlNG 3,011,480

IMPACT Toor.

Filed May 6, 1960 3 Sheets-Sheet 1 BNR@ Hls TOR` Dec. 5, 1961 .1.5. VILMERDING 3,011,480

IMPACT Toor.

Filed May 6, 1960 3 Sheets-Sheet 2 y INVENTQR -JoH/v a. v/L 4E/wav@ Dec. 5, 1961 Filed May 6, 1960 IMPACT TOOL 5 Sheets-Sheet 3 |28 '26 .|eo n4 95 y n El o 94 12 74 \\\\\/38 es 96 927s as ///J//A FIG. 4

' I INVENTOR JOHN B. V/LMERNG HIS ATTORNEY` ilnited States Patent @hice 3,011,480 Patented Dec. 5, 1961 3,011,430 IMPACT TOL .lohn B. Vilmerding, Moorestown, NJ., assigner to Ingersoll-Rand Company, New York, N.Y., a corporation of New Jersey Filed May 6, 1960, Ser. No. 27,374 13 Claims. (Cl. 121-33) rl`his invention relates to automatic shut-oil devices for power wrenches and the like.

In many types of Workwhere power wrenches are employed, a series of boits are brought up to a certain torque and then arbitrarily they are turned a fraction of a turn further so as to properly stress the bolt and pull the bolted pieces together. Heretofore operators have depended upon their eyesight to tell when the bolt has been turned suicientiy. It is a very simple thing to misjudge the amount of turning of a nut or bolt by this method, and

there has been a need for a wrench which would automatically turn some predetermined degree, then stop.

lt is an object of this invention to provide such an automatic shut-off.

, Other objects and advantages of the invention will be in part obvious and in part pointed out hereinafter.

The drawing illustrates a preferred form of the invention as applied to a hand tool and includes FIGURE 1, a longitudinal view of the hand tool, in this instance a wrench, front portions of the casing and interior being shown in longitudinal section, other parts being shown in dashed lines to indicate the general arrangement of the motor and its control features,

FlG..2 is a longitudinal view partly in section showing the details of the control mechanism,

FIG. 3 is a cross section of the tool taken along the line 3-3 looking in the direction of the arrows, and

FIG. 4 is a longitudinal section along the line 4 4 of FlG. 3 looking in the direction of the arrows.

The line 2-2 and the arrows thereof indicate the longitudinal section along which FIG. 2 is taken and indicated in FlG. 3.

Referring to the drawing and more particularly to FIG. l, the invention is shown applied to a type of tool commonly known as an impact wrench, the reason for this being that these tools are much lighter for any driven degree of torque to be developed, althoughit will be understood that the invention is applicable to wrenches whether electric driven, automatic, or otherwise, there 4being in all cases a motor here shown as a pneumatic motor whose object is to drive a suitable spindle 12 adapted to be tted with the work engaging implement, in this case it being a socket 14 for engagement with the nut 16.

In FIG. l, for simplicity, spindle 12 is the anvil of an impact wrench which may be of the character shown .in limerson et al., latent No. 2,160,150 of May 30, 1939 in which the motor driven hammer 18 drives the spindle 12 by impact intermittently partly under the influence of a spring 20. The tool is provided with a casing indicated at 22 at the rear of which is provided a .suitable grip or andle 24 and as is usual in such a tool, air is supplied at an aperture 26 (FIG. 2) in the handle to receive a suitable coupling 23 leading to a source ofcompressed air (not shown), a throttle valve 30 in this instance controlled by a trigger 32 cooper-ating with an actuating plunger 34.

The details of the throttle valve are unimportant in this connection, it beingsuicient .to state that the throttle valve 30 controls ilow of air from the inlet 26 toa supply port 36 passing through the handle portion 24 and into a portion of the casing 22 which for convenience in this connection will -be called a valve chamber member' As best shown in FIG. 3, the valve chamber member 38 is provided means to control the flow of energy to the motor which in this instance is a valve 40 positioned in a chamber having two portions 42 and 44. The chamber portion 42 is the terminus of the supply port 36 and the chamber portion 44 communicates with a port 46 leading to motor 10. Between these chamber portions 42 and 44 is provided ka valve seat 48 for the valve 40 which is adapted to control the flow of air to the motor. Valve 40 is axially movable on and off its seat 48 and to this end is provided with a cylindrical guiding portion 50 slidable in a bushing 52 mounted in the valve chamber member 38. The valve 40 is necked down as at 54 between the guiding portion 50 and a head 56. Upon the head 56 is provided a renewable washer 58 backed by washer 60 held in place by a suitable cap screw 62. The valve 40 is biased to its open position by a spring 64 encircling the valve and bearing at one end against the l'bushing 52, at its other end against a ring 66 encircling.

the valve 40 and in turn bearing against a sleeve 68 interposed between the washer 58 and the ring 66.

The end of the guide portion 50 is exposed to atmospheric pressure and to this end is provided a slot '70 extending transversely of the valve chamber member 3S, this end of the valve 46 being exposed to atmospheric pressure it will be seen that any considerable air pressure in the chamber portions. 42 and 44 will overcome the biasing of spring 64 and tend to close the valve whereupon when the washer 58 is seated on the seat 4?; communication ceases between the port 36 and the port 46 to shut down the motor 10.

Means is provided which is actuatable by the turning of the spindle 12 to Control the operation of valve 40 and thereby to shut ofi the supply of energizing compressed air to the motor 10. To this end is provided a latch member 72 extending into the slot 70` and movable axially therein and rotatably in a sleeve bearing 74 mounted in the slot 7 0.

On the head of latch member 72 is an arm '76 which is movable into and out of engagement with the end 50 of the valve 40. As has been said above, it is desired that actuation of the valve 40 should be controlled by the latch 72 which in turn is actuatable by a member or means under the control of the spindle 12, that is to say upon a predetermined degree of rotation ofthe spindle 12, the latch 72 should release the valve 40 thereby automatically controlling operation of the motor 10. To this purpose there is provided a rod 78 fixedly attached to the spindle 12 as by a key 80. Rod `'78 extends lengthwise over the tool and preferably axially and through the valve chamber member 38. To house the mechanism for controlling the operation of'latch 72, valve chamber member 3S` is provided with a .cavity 81 across which latch member 72 extends to a bearing 82 mounted in an outer wall of said member 38. Rotatably mounted on rod 78 (FIG. 2) is a rotatable member 84 having teeth S6 forv engagement with a dog 88 mounted on the rod like shank of the latch 72.V To hold the dog S8 against rotation with respect to the latch 72, the shank of the latch is hexagonal as shown at ,90 so the interior of the dog 88 is likewise hexagonal so that the dog may slide on shank part 90 for purposes more apparent hereinafter. Dog 88 is provided with a tooth 92 to engage one or another of the teeth 86. YLatch member 72 being both rotatably and axially movable in its bearings 74 and 82 is biased against both such movements. y

Axial movement is resisted by a coil spring 94 encircling the latch 72 adjacent the bearing 8-2 and bearing against a collar 96 pinned to latch 72. Collar 96 forms a stop for the dog 88' as to its motion along the hexagonal part 90 of latch 72. As will be seen most clearly in FIG. 3, latch member 72 is normally held in its position in which the tooth 92 engages teeth 86 of the rotatable member 84. On ac- 3 count of engagement of the portion 50 with the arm 76, as has been described above, in operating condition, the valve 40 is urged by air pressure in chamber portions 42 and 44 toward its closed position.

Upon axial movement of the latch 72 to disengage the portion 50 of valve 40, a plunger 98 is adapted to rota-te latch 72 so that tooth 92 will disengage teeth 86 on rotatable member 84. Plunger 98 is adapted to reciprocate in the bore 100 in the direction transverse to latch 72 and in line with arm 76. Plunger 98 is provided with a head 102 of slightly larger diameter than the bore 100 and tits into a bore 104 which contains also a coil spring 106 held in place by a screw plug 10S.

From the a-bove it will be seen that rotation of ratchet member S4 in a clockwise direction as seen in FIG. 3 will move the latch 72 axially. Asbest shown in FIG. 2, such rotation is produced by mutual engagement of a pair of pins, one, shown at 114i, mounted on ratchet member 84 and extending upwardly into the path of the other pin 112 mounted on a cylindrical disc member 114 mounted on rod 78 for rotation therewith.`

Also mounted non-rotatably on rod 7 8 is a stop member 116 which fixes the initial position of rotatable member 84 with respect to shaft 73. To bring the ratchet wheel 84 to this position is provided a spring 11S one end of which engages a collar 120 non-rotatably mounted on rod 7S and the other end tted into a hole 122 in the ratchet member 84. Spring 118 being of the torsion variety wili bring the pin 110 into abutment with the stop member 116 whenever ratchet member 34 is disengaged.

As will be seen, the degree of rotation of rod 7S before engagement of pins 110 and 112 with each other will depend upon the initial position of pin 112 with respect to pin 110. Provision is made for adjustment of such position and for this purpose the end of the rod 7S is formed hexagonally as at 124 and the disc 114 carrying the pin 112 is removable from the end of the rod 7S endwise and replaceable in a variety of positions of the pin 112. Disc 114, in this instance, is heid on the rod 78 by a thumb screw 126 which will also hold in place an index 12S indieating the position in which pin 112 lies with respect to pin 110'.

As indicated, the motor is of the Well known vane type, and if desired, may be reversible. In such case a suitable reversing valve 13%) may be provided which is adapted to cooperate with the motor ports 132 and 134 in one of its rotated positions bein-g adapted to alternatively connect those ports with a suitable exhaust port 136 and the supply passage 138 through the valve body in connecting with the motor supply passage 46.

In the reversed position of valve 135, the latch mechanism would cease to function in its usual manner although no harmful elects would probably occur since teeth 92 and 86, because of their angularity at their back faces, would slide over one another without damage. Still no beneficial effect could be imagined under such circumstances.

To avoid this condition and to render the latch mechanism completely ineffective, the valve 40 is provided with a tail portion 140 extending across slot 7G into a bushed bore 142. Bushing 144 in the bore 142 is provided with a transverse aperture 146 adapted to register in shut-o position with a notch 148 in the tail 140. A hand operated plunger is slidable in a bore 152 in the valve chamber member 38 and has a knob 154 for thumb contact. An enlarged -bore 156 houses a ilange 158 on the plunger 150 to enable coil spring 160 to press plunger 150 in its outermost position. The bore 152 is transverse to the axis of the valve 40 and so positioned that the inner end of plunger 15) is adapted to enter the aperture 146 in bushing 144 for engagement with the notch 148 in the tail 140 of the valve 40. In such engaging position the valve 40 is inoperative and consequently the latch 72 is likewise inoperative.

This will take care of conditions when the wrench is to be used as in ordinary practice to run down nuts, release them, or using the latch mechanism to give them their nal tightening partial rotation.

The operation should be obvious from the above description but it may be summarized as follows:

Starting with the throttle valve closed no air can pass the Valve 30 and inasmuch as there is no air under pressure in chamber portions 42 and 44, spring 64 will push the valve 40 outwardly until the head of cap screw 62 hits the end of the plug 164, by which access to the interior of the valve casing is provided. This will pull the portion 5G of valve 40 out of the way of arm 76 which allows spring 94 to push latch 72 to the right, as seen in FIG. 3. This is the normal oir position of things in general or this tool. Even though there might have been air under pressure in chamber portion 42, this would leak out into the chamber portion 44 and thence into motor 10 where it would soon leak out since port 166, which is of very restrictive size so as to be relatively inoperative under ordinary operating conditions, will equalize pressures in chamber portions #i2 and 4d. As soon as the throttle valve 30 is opened, however, chamber portions 42 and i4 till with air admitted through port 36 and the guiding portion Sil of valve 461 pushes against arm 76 of latch 72 to rotate the latter' bringing dog tooth 92 into engagement with teeth 86 of ratchet member 84. Meanwhile, of course, ratchet member 84 under the iniiuence of spring 118 has rotated until pin 11@ lies against stop member 116. In this state of affairs, air passes to motor 10 by way of passage 35, chamber portion 42, chamber portion 44, passage le, passage 133 in the valve 130 to actuate motor 141, and then exhausting through exhaust port 136. Due to the unbalanced air pressures on valve 4G, valve 4d moves forward to push against arm 76 of latch 72 to bring tooth 92 of latch 72 into engagement with one or another of ratchet teeth S6. It the tooth 92 does not meet the other teeth squarely, it will slide along the hexagonal part or latch member 72 until it is able to seat properly.

lt is to be noted that the slida-ble mounting of dog 85 serves also to prevent damage to the mechanism if the tool is run in reverse and the knob 154 for some reason is not pushed down. When this happens the rotatable member 84 will force dog 88 towards the right sliding on the hexagonal shank 96 of latch 72, until dog tooth and rotatable member teeth are no longer in engagement. Since this will permit partial closing of the shutoi valve the tool will lose most of its power. However, to assure that dog 88 will slide back to its original position when the tool is stopped, a spring is mounted on latch member 72, as shown in FIGS. 3 and 4, this spring being of necessity weaker than spring 94.

Meanwhile, motor 10 has started up causing rotation of the spindle 12 and rotation of rod 78 whereupon pin 112 will approach pin 11d on rotatable member S4. The stop member 116 also advances accordingly, leaving the pin potentially able to rotate with rotatable member 84. This it is unable to do since the spring 94 opposes longitudinal motion of the latch 72. Rotation of rod 78 continues until pin 112 reaches and contacts pin 110, whereupon the torque in rod 73 is suicient to overcome the compression of spring 94 and latch 72 accordingly moves axially to release arm 76 from the end of valve 40. Being released, valve 40 closes since the washer 58 rests on seat 4S the air supply is cut ofr" to the port 46 and the motor stops.

Meanwhile, spring pressed plunger 98 pressing against arm 76 rotates latch 72 and accordingly dog 88 disengages teeth 86 of the rotatable mem-ber. Torsion spring 118 thereupon snaps rotatable member 84 around until pin 110 hits stop member 116. Pin 112, however, stays put and now the pins 110 and 112 resume their original langular displacement with respect to each other ready for recycling.

This cannot happen however until valve 40 reopens `and it cannot however reopen until throttle valve 30 iis.'

closes. Throttle valve closing will occur when the operator releases pressure on the trigger 32. When the `supply of air to chamber portion 42 is cut of, that which -remains will leak out through bleeder port 166 into the chamber portion 44 and thence to the motor Where it is -able to escape since such motors are always leaky.

With the pressure in chamber portions 42 and 44 released, spring 64 is now in condition to return valve 40 to its original open position.

The operation is repeated as soon as lthe operator presses on trigger 32. y n

Thus, by the above construction -are accomplished, among others, the objects hereinbefore referred to.

I claim:

1. An automatic shut-oh for power Wrenches and the like having a motor and a spindle to be turned by the motor and adapted to be fitted with a work engaging implement to engage and turn a work piece relative to another work piece including means to control the flow of` energy to the motor, and means actuatable upon a predetermined degree of rotation of said spindle relative to said another work piece to operate said control means to shut off the supply of energy to said motor.

2. An automatic shut-off for power wrenches and the like having a motor and a spindle to be turned by the motor adapted to be fitted with a work engaging imple- 6 relative rotation thereof to cause said member to actuate said latch.

7. An automatic shut-olf for power wrenches and the like having a pneumatic motor, a throttle valve, and a spindle to be turned by the motor and adapted to be litted with a work engaging implement including a control valve associated with said throttle valve to shut off the supply of air to the motor, means to bias the control valve to normally open position, said valve having a pressure face to overcome said biasing means while said throttle valve is open, a latch to engage said control valve to oppose pressure on said pressure face and having a Vdog, a shaft rotatable with said spindle, a toothed member rotatable on said shaft engageable with the dog of said latch and adapted to move said latch to a position to disengage said valve, a trip member rotatable with said shaft, means biasing said toothed member and trip ment to engage and turn a work piece relative to another e work piece, including means to control the ilow of energy to the motor, and means actuatable upon a predetermined degree of rotation of said spindle relative to said another work piece to operate said control means and cooperative with said control means -to shut off the supply of energy to said motor.

3. An automatic shut-off for power wrenches andthe like having a pneumatic motor and a spindle to be'turned by the motor and adapted to be itted with a work engaging implement including a valve for controlling the ow of motive air to the motor, a member actuatable by the spindle in accordance with the turning of the spindle, a latch for holding said valve in open position, and means controlled by said member to release said latch.

4. An automatic shut-olic for power wrenches and the like having a pneumatic motor and a spindle to be turned by the motor and adapted to be iitted with a work engaging implement including a valvev for admitting air to said motor, means for biasing said valve to its open position, a member actuatable by the spindle in accordance with the turning of the spindle, a latch for holding said valve in open position, means controlled by said member to release said latch, and means to overcome said biasing means to close said valve. v

5. An automatic shut-olf for power wrenches and the like having a pneumatic motor and a spindle to be turned by the motor and adapted to be tted with `a work engaging implement to engage and turn a work piece relative to another work piece including a valve for admitting air to said motor and normally biased to its opent' member to a predetermined angular relation to each other, and projections on said toothed member and said trip member mutually engageable to cause latch releasing rotation of said toothed member.

8. An automatic shut-off for power wrenches and the like having a pneumatic motor,'a throttle valve, and a spindle to be turned by the motor and adapted to be fitted with a work engaging implement as set forth in claim 7 in which means is provided to adjust said predetermined angular relation.

9. An automatic shut-off for power Wrenches and the like having a pneumatic motor, a throttle valve, and a spindle to be turned by the motor and adapted to be fitted with a work engaging implement as set forth in claim 7 in which said latch is rotatable into dog engaging relation with said toothed member and is provided with an arm engageable by said control valve to maintain vsuch relation, said latch being axially slidable to disenposition, a latch for holding said valve in open position,

a shaft rotatable with said spindle, means cooperative with said shaft upon a predetermined degree of rotation of said spindle relative to said another work piece to actuate said latch to disengage said valve..

6. An automatic shut-off as set forth in claiml 5 in which said means cooperating with said shaft to actuate saidl latch includes an element Xed torotate with said shaft, a member rotatable with respect to said shaft and =releasably engageable with the latch and adapted to actuate said latch, means biasing said member and saidr element to a predetermined position, and projections on said element and said member mutually engageable upon and disengagement of the dog and toothed member.

10. An automatic shut-off for power wrenches and the like having a pneumatic motor, a throttle valve, and a spindle to be turned by themotor and adapted to be tted cludes means to hold said latch againstactuation with respect to said valve.

` 13. The apparatus of claim 3 wherein said means includes a plunger to engage the valve in position out of engagement with the latch.

References Cited in the file of this patent UNITED STATES PATENTS Romaine ...r Nov. 22., 1938 L 2,246,910 Amtsberg June 24, 1941 2,422,733 Iimerson n n- AJune 24, 1947 2,569,244 Larson Sept. 25, 1951 2,814,277 Jimerson Nov. 26, 1957 FOREIGN PATENTS 537,702 Belgium Apr.26, 1954 

